Corneal implant and method of manufacture

Abstract

Prosthetic implants designed to be implanted in the cornea for modifying the cornea curvature and altering the corneal refractive power for correcting myopia, and myopia with astigmatism, such implants formed of a micro-porous hydrogel material.

I claim:  
     
       1. A corneal implant for correcting myopia with astigmatism, comprising: 
       (a) a body formed of an optically clear, biocompatible, material having an index of refraction substantially the same as that of corneal tissue;  
       (b) the body having an outer ring-shaped portion that is solid and defines an opening; and  
       (c) the body including a second solid portion that fills in a portion of the opening, the second solid portion being located in a position to be implanted under a flattened portion of an astigmatic eye.  
     
     
       2. The implant of  claim 1 , wherein the body has an outer edge with a thickness of the edge being less than about 15 micrometers. 
     
     
       3. The implant of  claim 1  or  2 , wherein the second solid portion comprises a rib extending across the center of the opening. 
     
     
       4. The implant of  claim 3 , wherein the rib is squared off where it joins the ring-shaped portion. 
     
     
       5. The implant of  claim 4 , wherein the rib is rounded where it joins the ring-shaped portion. 
     
     
       6. The implant of  claim 1 , wherein the biocompatible, material is a microporous hydrogel. 
     
     
       7. The implant of  claim 6 , wherein the microporous hydrogel has a water content greater than 40% up to approximately 90%. 
     
     
       8. The implant of  claim 6 , wherein the microporous hydrogel has passageways to permit nutrient and fluid transfer, said passageways being small enough to act as a barrier against tissue growth. 
     
     
       9. The implant of  claim 6 , wherein the microporous hydrogel is made from at least one hydrophilic monomer which is polymerized and cross-linked with at least one multi- or di-olefinic cross-linking agent. 
     
     
       10. The implant of  claim 1 , wherein the body has an outer edge with a thickness of the edge being less than about two keratocytes. 
     
     
       11. A method of implanting a corneal implant for correcting myopia with astigmatism, comprising the steps of: 
       (a) cutting away a portion of the outer surface of a cornea;  
       (b) implanting a lens on the exposed surface of the cornea with a body formed of an optically clear, biocompatible, material having an index of refraction substantially the same as that of corneal tissue, the body having an outer ring-shaped portion that is solid and defines an opening, the body including a second solid portion that fills in a portion of the opening, the second solid portion being located in a position to be implanted under a flattened portion of an astigmatic eye; and  
       (c) replacing the portion of the cornea that was cut away.  
     
     
       12. The method of  claim 11 , wherein the body has an outer edge with a thickness of the edge being less than about 15 micrometers. 
     
     
       13. The implant of  claim 11 , wherein the biocompatible, material is a microporous hydrogel. 
     
     
       14. The implant of  claim 13 , wherein the microporous hydrogel has a water content greater than 40% up to approximately 90%. 
     
     
       15. The implant of  claim 13 , wherein the microporous hydrogel has passageways to permit nutrient and fluid transfer, said passageways being small enough to act as a barrier against tissue growth. 
     
     
       16. The implant of  claim 13 , wherein the microporous hydrogel is made from at least one hydrophilic monomer which is polymerized and cross-linked with at least one multi- or di-olefinic cross-linking agent. 
     
     
       17. The implant of  claim 11 , wherein the body has an outer edge with a thickness of the edge being less than about two keratocytes. 
     
     
       18. A corneal implant for correcting myopia, comprising: 
       (a) a body formed of an optically clear, biocompatible, material having an index of refraction substantially the same as that of corneal tissue;  
       (b) the body having an outer ring-shaped portion that is solid and defines an opening; and  
       (c) the body having an outer edge with an outer edge with a thickness of the edge being less than about 15 micrometers.  
     
     
       19. The implant of  claim 18 , wherein the body is generally circular in shape. 
     
     
       20. The implant of  claim 18 , wherein the biocompatible, material is a microporous hydrogel. 
     
     
       21. The implant of  claim 20 , wherein the microporous hydrogel has a water content greater than 40% up to approximately 90%. 
     
     
       22. The implant of  claim 20 , wherein the microporous hydrogel has passageways to permit nutrient and fluid transfer, said passageways being small enough to act as a barrier against tissue growth. 
     
     
       23. The implant of  claim 20 , wherein the microporous hydrogel is made from at least one hydrophilic monomer which is polymerized and cross-linked with at least one multi- or di-olefinic cross-linking agent. 
     
     
       24. The implant of  claim 18 , wherein the body has an outer edge with a thickness of the edge being less than about two keratocytes. 
     
     
       25. A method of implanting a corneal implant for correcting myopia, comprising the steps of: 
       (a) cutting away a portion of the outer surface of a cornea;  
       (b) implanting a lens on the exposed surface of the cornea with a body formed of an optically clear, biocompatible, material having an index of refraction substantially the same as that of corneal tissue, the body having an outer ring-shaped portion that is solid and defines an opening; and  
       (c) replacing the portion of the cornea that was cut away.  
     
     
       26. The method of  claim 25 , wherein the body has an outer edge with a thickness of the edge being less than about 15 micrometers. 
     
     
       27. The implant of  claim 25 , wherein the biocompatible, material is a microporous hydrogel. 
     
     
       28. The implant of  claim 27 , wherein the microporous hydrogel has a water content greater than 40% up to approximately 90%. 
     
     
       29. The implant of  claim 27 , wherein the microporous hydrogel has passageways to permit nutrient and fluid transfer, said passageways being small enough to act as a barrier against tissue growth. 
     
     
       30. The implant of  claim 27 , wherein the microporous hydrogel is made from at least one hydrophilic monomer which is polymerized and cross-linked with at least one multi- or di-olefinic cross-linking agent. 
     
     
       31. The implant of  claim 25 , wherein the body has an outer edge with a thickness of the edge being less than about two keratocytes.